Gelled printing ink compositions

Abstract

A smooth stable viscous gelled printing ink composition comprising a mixture of water, a gelling agent, a chelating agent, and a colorant or pigment, property enhancing additives evenly dispersed into the mixture, and an alkaline electrolyte viscosity increasing agent that raises the pH of the mixture and forms a smooth homogeneous stable gel with a viscosity level having the consistency of a custard or jelly. In addition to the colorants or pigments, additives may also include drying oils, resins, surfactants, film forming components, water flight agents, and other additives. The stabilized gel prevents separation and settling of the homogeneously suspended colorants, pigments, and property enhancing additives, and significantly improves storage stability. The ink compositions do not require shaking, stirring, or mixing prior to use are fast drying on paper, and do not dry on the printing press, in the storage containers, or in the ink jet or bubble jet injector nozzles. The gelled ink compositions with property enhancing additives also have improved non rub-off characteristics, excellent printability, high color strength, good water balance, less mist, and sharp halftone reproduction.

What is claimed is:  
     
       1. A stable viscous gelled printing ink composition for use in printing presses, ink jet printers, and bubble jet printers, comprising a mixture of: 
       water;  
       from about 0.01% to about 10% by weight of a cross-linked polyacrylic acid gelling agent to significantly lower the pH of the mixture;  
       from about 0.001% to about 5% by weight of ethylene diaminetetraacetic acid as a chelating agent to bind excess ions in the mixture;  
       from about 5.0% to about 50% by weight of a colorant selected from the group consisting of organic dyes and pigments, and inorganic dyes and pigments to produce a uniform color;  
       at least one property enhancing additive evenly dispersed into the mixture in an amount sufficient to enhance the properties of the ink composition; and  
       from about 0.002% to about 3% by weight of an alkaline electrolyte viscosity increasing agent selected from the group consisting of triethanolamine, a mixture of sodium hydroxide and water, and a dilute mixture of an amine component to raise the pH of the mixture and form the mixture into a smooth homogeneous stable gel printing ink with a viscosity level having the consistency of a custard or jelly; wherein  
       said gelled printing ink composition does not require shaking stirring or mixing prior to use, is fast drying on paper, and does not dry in a printing press, in storage containers, or in ink jet or bubble jet injector nozzles.  
     
     
       2. The viscous gelled printing ink composition according to  claim 1 , further comprising 
       a surfactant in an effective amount sufficient to reduce the surface tension of the mixture.  
     
     
       3. The viscous gelled printing ink composition according to  claim 1 , wherein 
       said at least one property enhancing additive is selected from the group consisting of binders, drying oils, resins, film forming agents, water flight agents, and adhesion promoters.